Spatiotemporal Variability in Convective Cells and their Thermodynamic and Aerosol Environments during TRACER

In June-September 2022, a team from Texas A&M University (TAMU) conducted mobile radiosonde and aerosol measurements as part of the DOE-sponsored Tracking Aerosol Convection Interactions Experiment (TRACER) field campaign in and around Houston, Texas. A primary goal of this field campaign was to determine the potential aerosol influences on ordinary convection in the vicinity of an urban region with diverse aerosol sources (e.g., heavy industry, petrochemical refineries, vehicular traffic). Given the proximity of the Gulf of Mexico and Galveston Bay to the study region, sea- and bay-breeze circulations are ubiquitous features of this region during the study period, and they often serve as a focus for convection initiation. Thus, the specific goal of the mobile TAMU team was to sample both the meteorological and aerosol variability across mesoscale air masses, using similar instrumentation to the fixed-site DOE facilities.

In this poster, we present an overview of our deployment strategy and present results documenting the variability in convective cell environments as well as radar-derived cell characteristics as a function of their background airmass. First, early and late afternoon differences in the thermodynamic conditions (e.g., CAPE, CIN, precipitable water) in continental (inland of the sea-breeze front), maritime (on the coastal side of the sea-breeze front), and outflow (from ongoing or previous convection) air masses are compared between the TAMU measurements and DOE ARM sites. Next, we compare characteristic surface and boundary layer concentrations of aerosols that could serve as cloud-condensation nuclei (CCN) or ice nucleating particles (INP) within these air masses. Finally, radar observations from the National Weather Service S-band WSR-88D and the DOE C-band Scanning ARM Precipitation Radar (CSAPR2) are used to compare convective cell attributes as a function of their parent airmass (continental, maritime, outflow, or along the sea-breeze front). WSR-88D measurements are used to provide a climatology of cell attributes (e.g., durations, maximum echo top heights, cell area, maximum reflectivity, precipitation onset time after initiation) in each air mass. The CSAPR2 was run in a novel cell-tracking mode featuring targeted PPI sectors and RHIs, which we use to provide and compare vertical profiles of reflectivity and polarimetric variables (e.g., differential reflectivity columns) for a subset of the well-sampled cells. We will discuss the potential impacts and relative importance of thermodynamic versus aerosol variability on observed differences in convection across air masses.